running with a dog

Question
My wife likes to take our dog running with her (about 3-4 miles) 4 to 5 times per week. Today someone told her it was hard on the dogs joints to run for long distances, that dogs were only meant to run short distances.

The dog is a chow/golden retriever mix.

Is this hard on the dogs joints and can she (the dog) run for long distances?

Answer
if given too much exercise it can put stress on the joints.  You should take her for short walks every day and long walks/runs probably once.
German shepards usually suffer as a result of this.  in the wild, dogs dont run long distances to catch food. they are usually scavengers and only catch prey when in times of need.